diff --git a/Cargo.lock b/Cargo.lock
index fe3abe860..ce43fa28c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5160,7 +5160,7 @@ checksum = "9b4f627cb1b25917193a259e49bdad08f671f8d9708acfd5fe0a8c1455d87220"
 [[package]]
 name = "petri-attractor-steps"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "async-trait",
  "globset",
@@ -5191,7 +5191,7 @@ dependencies = [
 [[package]]
 name = "petri-driver"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "async-trait",
  "getrandom 0.3.4",
@@ -5211,7 +5211,7 @@ dependencies = [
 [[package]]
 name = "petri-engine"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "petri-ir",
  "serde",
@@ -5223,7 +5223,7 @@ dependencies = [
 [[package]]
 name = "petri-execution"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "async-trait",
  "petri-driver",
@@ -5247,7 +5247,7 @@ dependencies = [
 [[package]]
 name = "petri-executor"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "async-trait",
  "libc",
@@ -5262,7 +5262,7 @@ dependencies = [
 [[package]]
 name = "petri-executor-sandbox"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "async-trait",
  "petri-executor",
@@ -5284,7 +5284,7 @@ dependencies = [
 [[package]]
 name = "petri-frontend"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "marked-yaml",
  "petri-ir",
@@ -5298,7 +5298,7 @@ dependencies = [
 [[package]]
 name = "petri-frontend-attractor"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "minijinja",
  "petri-frontend",
@@ -5315,7 +5315,7 @@ dependencies = [
 [[package]]
 name = "petri-frontend-fabro"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "petri-frontend",
  "petri-frontend-attractor",
@@ -5331,7 +5331,7 @@ dependencies = [
 [[package]]
 name = "petri-frontend-native"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "petri-frontend",
  "petri-ir",
@@ -5342,7 +5342,7 @@ dependencies = [
 [[package]]
 name = "petri-ir"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "regex",
  "serde",
@@ -5355,7 +5355,7 @@ dependencies = [
 [[package]]
 name = "petri-runtime"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "async-trait",
  "petri-driver",
@@ -5376,7 +5376,7 @@ dependencies = [
 [[package]]
 name = "petri-steps"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "async-trait",
  "petri-executor",
@@ -5392,7 +5392,7 @@ dependencies = [
 [[package]]
 name = "petri-store"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "async-trait",
  "getrandom 0.3.4",
@@ -5407,7 +5407,7 @@ dependencies = [
 [[package]]
 name = "petri-testkit"
 version = "0.1.0"
-source = "git+https://github.com/lithoscomputer/petri.git?branch=main#e0e48d6d7f6b6af86e52a25e6abaf250f36874e6"
+source = "git+https://github.com/lithoscomputer/petri.git?branch=main#9925996f8ce751a38fe03b03723fff869a8eb153"
 dependencies = [
  "async-trait",
  "petri-driver",
diff --git a/lib/components/fabro-petri/src/engine.rs b/lib/components/fabro-petri/src/engine.rs
index 4d016f846..4174ba915 100644
--- a/lib/components/fabro-petri/src/engine.rs
+++ b/lib/components/fabro-petri/src/engine.rs
@@ -59,9 +59,7 @@ use petri_execution::{
 use petri_runtime::driver::lifecycle::ExecutionHooks;
 pub use petri_runtime::executor::Retention;
 use petri_runtime::executor::SecretProvider;
-use petri_runtime::{
-    DaytonaResources, DaytonaSandboxKind, LostSandbox, RunOptions, SandboxBackend,
-};
+use petri_runtime::{DaytonaResources, LostSandbox, RunOptions, SandboxBackend};
 use tokio::fs;
 use tokio_util::sync::CancellationToken;
 use tracing::{debug, info, warn};
@@ -192,9 +190,6 @@ pub async fn run(request: RunRequest) -> Result<RunOutcome, RunError> {
     options.run_key = Some(key.clone());
     options.retention = RETENTION;
     options.sandbox.backend = backend;
-    // Fabro runs on Daytona's generally available containers; Petri's VM
-    // default requires runner capacity that ordinary accounts may not have.
-    options.sandbox.daytona_kind = DaytonaSandboxKind::Container;
     if backend == SandboxBackend::Daytona {
         options.sandbox.daytona_resources = daytona_resources(&request.resources)?;
     }
@@ -406,7 +401,7 @@ fn error_chain(error: &RunError) -> String {
     parts.join(": ")
 }
 
-/// Keep the configured allocation, leaving an unspecified disk to Daytona.
+/// Overlay Fabro's configured allocation on Petri's runner defaults.
 fn daytona_resources(
     settings: &EnvironmentResourcesSettings,
 ) -> Result<DaytonaResources, RunError> {
@@ -420,7 +415,7 @@ fn daytona_resources(
         memory_mb: settings
             .memory
             .map_or(defaults.memory_mb, daytona_mebibytes),
-        disk_mb:   settings.disk.map(daytona_mebibytes),
+        disk_mb:   settings.disk.map(daytona_mebibytes).or(defaults.disk_mb),
     })
 }
 
diff --git a/lib/components/fabro-petri/tests/daytona.rs b/lib/components/fabro-petri/tests/daytona.rs
index 3e1a2e39b..8d4c72e5d 100644
--- a/lib/components/fabro-petri/tests/daytona.rs
+++ b/lib/components/fabro-petri/tests/daytona.rs
@@ -35,6 +35,20 @@ async fn daytona_runs_forward_configured_resources_in_provider_units() {
     .await;
 }
 
+#[tokio::test]
+async fn daytona_accepts_an_explicit_disk_matching_the_provider_default() {
+    assert_snapshot_request(
+        EnvironmentResourcesSettings {
+            disk: Some("3GB".parse().unwrap()),
+            ..EnvironmentResourcesSettings::default()
+        },
+        2,
+        4,
+        Some(3),
+    )
+    .await;
+}
+
 #[tokio::test]
 async fn daytona_decimal_memory_meets_the_runner_minimum_without_defaulting_disk() {
     assert_snapshot_request(